Daikin Altherma R Hybrid Installer's Reference Manual page 187

CHYHBH05+08AF + EHYKOMB33A
Daikin Altherma R Hybrid
4P471761-1E – 2020.10
Error code Cause
20, 21, 22, Sensor fault S2
23, 24
0 Sensor fault after self-
check
1 Temperature too high
2 S1 and S2 interchanged
4 No flame signal
5 Poor flame signal
6 Flame detection fault
8 Incorrect fan speed
29, 30 Gas valve relay fault
13
Possible solution
▪ Check wiring
▪ Replace S2
Replace S1 and/or S2
▪ Air in installation
▪ Pump is NOT running
▪ Insufficient flow in installation
▪ Radiators are closed
▪ Pump setting is too low
▪ Check cable set
▪ Replace S1 and S2
▪ Gas tap is closed
▪ No or incorrect ignition gap
▪ Gas supply pressure is too low or fails
▪ Gas valve or ignition unit is NOT powered
▪ Condensate drain blocked
▪ Check adjustment of gas valve
▪ Replace ignition cable and spark plug cap
▪ Replace ignition unit
▪ Replace boiler controller
▪ Fan catching on casing
▪ Wiring between fan and casing
▪ Check wiring for poor wire contact
▪ Replace fan
Replace boiler controller
Troubleshooting
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Installer reference guide
187